塔里木河下游河岸胡杨(Populus euphratica)林耗水过程模拟

Simulation of Water Consumption of Populous euphratica Forests in the Lower Reaches of the Tarim River

选择塔里木河下游主要植物胡杨(Populus euphratica)林,以大气温度、太阳净辐射、大气相对湿度、冠层顶风速、地下水位和胡杨树茎横截面积为影响胡杨林耗水量的自变量,基于最小二乘法建立了多重线性回归模型、非线性回归模型和完全二次回归模型,并应用模型对塔里木河下游河岸胡杨林的耗水过程进行了日尺度上的模拟研究。结果表明:3个回归模型均表现出较好的模拟效果,其中完全二次回归模型的模拟精度最高,模型中大气温度、地下水位和胡杨树茎横截面积是影响胡杨耗水量的诸多环境因子中最敏感的因子;胡杨林的耗水量观测值与模拟值表现出较好的相关性,3个回归模型的模拟值与观测值的相关系数依次分别为0.6793、0.7299、0.7574,其相对误差分别为28.7%、26.1%、22.9%,其显著性水平均通过95%显著性检验;3个回归模型中完全二次回归模型具有使用简便、影响因子易测定、有一定精度等优点,能够更好刻画植被腾发量的复杂非线性特性,为干旱区自然植被耗水量估算、模拟和生态需水量计算提供了新的思路和方法。

The article taking the representative natural vegetation(Populus euphratica)in the lower reaches of Tarim River as the test vegetation,the air temperature,net solar radiation,atmospheric humidity,wind speed on the canopy top edge,groundwater level and cross sectional area of the P.euphratica,as initial influence factors of model based on the field test.Multiple linear regression model,nonlinear regression model and complete quadratic regression model were established based on the least square method;transpiration of the populous euphratica in the lower reaches of Tarim River was simulated by using the model.Results showed that the three regression models showed better simulating effect.Simulation accuracy of the complete quadratic regression model was higher than that of the other two models.The air temperature,groundwater level and cross sectional areas of the P.euphratica were the main factors affecting the transpiration of populus euphratica forest in the models.Transpiration observed and simulated values of populus euphratica forest showed better correlation.The coefficients of correlation between observed and simulated for transpiration of P.euphratica of the three models were 0.6793,0.7299 and 0.7574,respectively;the average relative error of simulated value with observed value for transpiration of that were 28.7%,26.1% and 22.9%,respectively.All significance level of them passedα=0.05.In that the complete quadratic regression model test against experimental data showed a good agreement between observed and simulated transpiration of the populous euphratica,it presented the advantage of ease to use,impact factor determination easier and a certain precision.The model provided a new effective and feasible way for the evaluation of natural vegetation evapotranspiration and the calculation of ecological water requirements.